Particle Sizing by Photon Correlation Spectroscopy Part I: Monodisperse latices: Influence of scattering angle and concentration of dispersed material

Abstract The possibilities and limitations of Photon Correlation Spectroscopy as a practical tool for particle sizing are revisited. In a first step, well characterized monodisperse polystyrene latices with particle sizes ranging from about 30 nm to about 2 μm were examined in five different industrial and academic laboratories. Particular attention was paid to the effect of particle concentration and scattering angle. It turned out that for a particle diameter less than 0.5 μm reliable particle sizes can be obtained. In the range of 0.5 to 1 μm this was only possible within a very narrow range of concentration of dispersed material. For the largest size investigated (about 2 μm) the PCS measurements were less reliable which was reflected in a considerable variation of the results.